Radio, miracle of the 20th century ... a story of human achievement that stands unrivalled in the history of humanity, together with a colorful portrayal, giving a broad, general view of the whole subject of wireless telegraph and telephone and its marvelous development (1922)
Drinker, Frederick E. [from old catalog], Lewis, James G., [from old catalog] joint author · [Philadelphia, Printed by National publishing co.] · leaf 271
e high voltage necessaryin the first case to break down the gap. Events repeatthemselves as long as the key is pressed down. Thus it is seen that when the key is pressed in part A,figure 11, there are 400 wave trains per second radiatedfrom the antenna. If the buzzer contacts were changedso as to… … If an alternating-current generator were used as thesource of power (used in A, fig. 11), the number of wavetrains would be twice the frequency of the alternations,for the spark-gap would break down at the highest posi-tive voltage and again at the highest negative voltage—that is, twice in one…
Radio
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